1. Field
The following description relates to an apparatus and a method for balanced power amplification.
2. Description of Related Art
A wireless power refers to energy that is transferred from a wireless power transmitter to a wireless power receiver through magnetic coupling. Accordingly, a wireless power transmission and charging system includes a source device and a target device. The source device may wirelessly transmit a power, and the target device may wirelessly receive a power. The source device may be referred to as a wireless power transmitter, and the target device may be referred to as a wireless power receiver.
The source device includes a source resonator, and the target device includes a target resonator. Magnetic coupling or resonance coupling may be formed between the source resonator and the target resonator.
In a transmitter for wireless communication or wireless power transmission, high energy efficiency and safety of operation may be factors. For example, a power amplifier (PA) may correspond to one of a number of components of the transmitter that cause the greatest effects on performance of the transmitter. High energy efficiency and safety of operation may be needed for the PA. The PA may be connected to a transmitting antenna such that the PA may include unstable load conditions, which may be changed depending on an external environment.
Generally, a PA of a very high frequency band may be designed under a condition that the PA may include a load of about 50 ohms (Ω). Under the preceding condition, the PA may provide an excellent performance. However, when the load is changed, the PA may experience a drastic change in overall performance, for example, an output power, efficiency, linearity, and/or the like. One response to the change in the performance resulting from the change in the load may be to use an isolator between an output end of the PA and an input end of a transmitting antenna connected to the PA.